Neuronal Communication

Question 1

Pacinian corpuscle

Answer 1

A pressure sensor found in the skin

Question 2

Transducer

Answer 2

A cell that converts one form if energy into another/in to electrical impulse

Question 3

Sensory receptors

Answer 3

Mostly transducers which can detect changes in our surroundings

Question 4

Structure of the pacinian corpuscles

Answer 4

Oval-shaped consists of a series of consecutive rings of connective tissues wrapped around the end of a nerve cell.

Question 5

What do pacinian corpuscles respond to?

Answer 5

Changes in pressure therefore stop responding when pressure is constant.

Question 6

What can cause sodium channels to open

Answer 6

Changes in pressure/ any stimulus

Question 7

What ion is inside the neurone

Answer 7

Potassium

Question 8

What ion is outside the neurone

Answer 8

Sodium

Question 9

Why can potassium ions leak out of the cell

Answer 9

The membrane is more permeable to potassium

Question 10

What enhances the negative potential of a neurone

Answer 10

The presence of negatively charged anions

Question 11

What effect the number of sodium channels opened

Answer 11

The intensity of the stimulus.

Question 12

structure of neurones.

Answer 12

long, many gated ion channels, sodium potassium pump, dendrites

Question 13

how many peripheral neurones in vertebrates are myelinated neurones.

Answer 13

one third

Question 14

what does the myelinated sheath do?

Answer 14

prevents the movement of ions across the neurone membranes.

Question 15

what is the polar state of the neurone?

Answer 15

-70mv

Question 16

what is the threshold value?

Answer 16

-50mv

Question 17

what causes voltage gated sodium channels to open after the threshold?

Answer 17

positive feedback loop.

Question 18

what is the maximum potential of the neurone?

Answer 18

30mv

Question 19

what causes the potential difference to be brought back to negative

Answer 19

potassium ions diffusing out of the cell.

Question 20

the potential diff overshoots what is this?

Answer 20

hyperpolarisation

Question 21

what is the refractory period?

Answer 21

the point were potassium and sodium are brought back to their original sides with the sp pump.

Question 22

What is inside a cell body?

Answer 22

The nucleus many mitochondria and ribosomes

Question 23

Why is the membrane more permeable to potassium ions the sodium ions when polarised?

Answer 23

Because some of the potassium channels are open

Question 24

What is the rating potential of the membrane

Answer 24

-70mV

Question 25

What is the threshold voltage?

Answer 25

-50mV

Question 26

What is the maximum voltage?

Answer 26

30mV

Question 27

What are local currents

Answer 27

When sodium ions are able to flow through the neurone causing depolarisation

Question 28

How do local currents occur?

Answer 28

Through diffusion

Question 29

Why don’t action potentials reverse in direction?

Answer 29

Because of the refractory period

Question 30

What are the gaps between the myelin sheaths called?

Answer 30

Nodes of Ranviar

Question 31

What is saltaory conduction

Answer 31

The jumping of action potentials from node to nod

Question 32

How fast is saltatory conduction

Answer 32

Up to 120ms-1

Question 33

What is the all or nothing rule?

Answer 33

All action potentials produce a depolarisation of 30mV

Question 34

How is intensity of stimulus detected?

Answer 34

Frequency of action potentials

Question 35

what is a cholinergic synapse

Answer 35

a synapse that uses acetylcholine as its neurotransmitter

Question 36

how wide is a synaptic cleft?

Answer 36

approximately 20nm wide

Question 37

what are the specialised features of the pre-synaptic bulb?

Answer 37

many mitochondria a large amount of smooth endoplasmic reticulum. voltage gated calcium channels.

Question 38

how does the post synaptic bulb react to the presence of a neurotransmitter?

Answer 38

they have specialised sodium ion channels which can respond to the neurotransmitter.

Question 39

what is the first step for the action of a synapse?

Answer 39

the voltage gated calcium ion channels open.

Question 40

what is the first step for the action of a synapse?

Answer 40

the voltage gated calcium ion channels open.

Question 41

what do the calcium ions cause inside the cell?

Answer 41

they cause the vesicles of neurotransmitters to move in the cell and bind with the membrane.

Question 42

what happens after the neurotransmitter binds to the receptor?

Answer 42

it causes the sodium channels to open.

Question 43

what is a EPSN?

Answer 43

a generator potential or a excitatory post-synaptic potential.

Question 44

what is the role of acetylcholinesterase?

Answer 44

it is an enzyme found in the synaptic cleft. it hydrolyses the acetylcholine to ethanoic acid and choline

Question 45

what is summation?

Answer 45

the effects of several excitatory post-synaptic potentials are added together.

Question 46

what is the main role of a synapse?

Answer 46

to connect two neurons together so a signal can be passed along.

Question 47

what is a summation?

Answer 47

occurs when the effects of several ESPN's are added together.

Question 48

what is temporal summation?

Answer 48

several action potentials in the same pre-synaptic neurone.

Question 49

what is spatial summation?

Answer 49

action potentials arriving from several different pre-synaptic neurones.

Question 50

what is the point of summations?

Answer 50

just one action potential isn't enough to reach the threshold potential.

Question 51

what can prevent the production of ESPN's ?

Answer 51

by the action of a ISPN.

Question 52

what would be useful in a reflex arc?

Answer 52

one presynaptic diverging innto many postsynaptic.

Question 53

what does it mean to become habituated?

Answer 53

after repeated stimulation to a stimulus a synapse may run out of vesicles containing the neurotransmitter. this means there is no longer a response.